Bonded metal-to-composite joints may require reinforcement either within the adhesive or within the first few plies of composite material due to high interlaminar stresses. These stresses may peak at the ends of the bondline or engagement region between the composite and the metal; therefore, ply distortions of the composite may be initiated at the end of the engagement region. Local reinforcement of the engagement region may enhance the structural strength of the joint.
One current technique of reinforcing a metal-to-composite joint may include use of a complex bond design such as a step lap joint which may effectively reduce the peak stresses between the metal and composite. Another reinforcement technique may include the use of mechanical reinforcements such as fasteners. However, these reinforcement techniques may be complex and expensive to manufacture.